The present invention is directed to semiconductor device packaging and, more particularly, to a bonded wire semiconductor device.
Semiconductor device packaging fulfils basic functions such as providing electric connections and protecting the die against mechanical and environmental stresses. Continued progress in reducing the size of the semiconductor dies and increasing functionality and complexity of the electronic circuits integrated in the dies requires size reduction of the packaging with the same or greater complexity of the electrical connections with external circuits.
Semiconductor devices are commonly packaged for surface mounting by embedding one or more semiconductor dies. Exposed electrical contacts for connection with external circuits are integrated in the package and are connected internally with electrical contact elements such as pads on the semiconductor die. Various techniques are available for connecting the exposed electrical contacts of the package with the embedded semiconductor die.
In a bonded wire package, the semiconductor die may be mounted on a substrate with the contact pads of the semiconductor die on its active face opposite from the substrate. Wires are then bonded to the contact pads of the semiconductor die and to inner ends of the exposed electrical contacts of the package to provide the internal connections. The substrate may be an electrically conductive lead frame, whose frame members are cut off and discarded during production after applying molding compound to encapsulate the semiconductor die, the bond wires and the inner ends of the exposed electrical contacts.
Size reduction of the dies and the packaging with the same or greater complexity of the electrical connections means that the pitch of the bond pads on the die and the pitch of the exposed electrical contacts is reduced. This aggravates the risk of defects caused by electrical contact between adjacent bond wires. Bond wires are not straight but extend in loops. The curvature of the bond wire loops can lead to sway of the loops from a vertical direction and sweep of the loops horizontally. Bond wire sway and sweep may especially be caused by flow of the molding compound during its injection.